1. Field of the Invention
The present invention relates to an apparatus for mounting an accessory to a camera lens.
2. Description of the Related Art
Generally speaking, a camera accessory, such as filter, close-up lens, hood, etc. is mounted to a camera lens by screwing the same into an accessory mounting screw portion (female thread) provided on the front end of a lens barrel of the camera lens. However, the accessory mounting screw portion is made of a single thread, and accordingly, the accessory engages with the accessory mounting screw (female thread) at only one circumferential portion on the periphery thereof. Therefore, it takes a relatively long time for an operator to meet the male thread of the accessory with the female thread of the accessory mounting screw portion. Furthermore, after the female thread meets with the male thread, it is necessary for an operator to rotate the accessory by several turns in order to completely engage the accessory in the accessory mounting screw portion. Therefore, the accessory mounting operation is a time consuming and troublesome operation. Because of this, an operator (photographer) may miss a shutter chance.
Accessory mounting devices using a permanent magnet or multiple thread which are free from the above-mentioned problem are also known.
However, in these conventional accessory mounting devices, in particular, a heavy accessory, such as a close-up lens having a plurality of lenses or a large hood tends to fall from the camera lens. In the case of a permanent magnet type mounting device, the heavy accessory can easily disengage from the camera lens when an external shock is applied thereto. On the other hand, in the case of a multiple thread type mounting device, because of the large lead of the multiple thread, when the camera is carried with the bottom facing up, the accessory can rotate and fall easily by the dead weight thereof.
An accessory mounting device using a type mounting bayonet is also known. However, in this accessory mounting device, it is necessary to register a mark of the bayonet with a reference mark of the camera lens.
Generally speaking, the above mentioned accessory mounting systems have a drawback, that is, an easy detachment of the accessory from the camera lens.